The movie will depict the controversial Rathergate scandal about six purported documents critical of President George W Bush's service in the Air National Guard in 1970s.
Redford will play CBS News icon Dan Rather and Blanchett will portray his producer Mary Mapes. It's adapted from Mapes' 2005 memoir "Truth and Duty: The Press, The President, And the Privilege Of Power", reported Deadline.
The film, to be directed by James Vanderbilt, will centre on the scandal that ensued during President Bush's re-election campaign after Rather reported on '60 Minutes II' that Bush had benefited from the powerful position of his father, then an ambassador and future president, to avoid service in Vietnam.